Sun chose the Tomcat JSP/Servlet container to serve as the Reference Implementation for Java developers. This makes using Tomcat as your development environment a solid choice if you desire Web application portability. As it is not atypical for security issues to be discovered in application servers, OpenLogic recommends upgrading to the latest available version of Tomcat.

License:

Tomcat
generally supports the latest servlet and JSP specifications, often receiving new
features like JSP Standard Tag Library (Jakarta JSTL) first, which makes it a wonderful place to
try out new features that will eventually be implemented by all the major container vendors.
JBoss Application Server works well with Tomcat
to provide a unified J2EE container.

Note: For information on installing Tomcat as a service for 64 bit Windows systems, please see the Tomcat FAQ